Multicellular velocity-modulated tube



June 22, 1954 R. BERTEROTTIERE MULTICELLULAR VELOCITY-MODULATED TUBE 3 Sheets-Sheet 1 Filed May 10, 1949 llllIlI/llllll June 22, 1954 R. BERTEROTTIERE MULTICELLULAR VELOCITY-MODULATED 3 Sheets-Sheet 3 Filed May 10, 1949 Patented June 22, 1954 UNITED STATES PATENT FFICEV 2,682,011 MULTICELLULAR YIEUICITY-MODULATED Ren Berterottiere, Pari Compagnie General d 2 Claims.

The present invention relates to velocitymodulated tubes of the type of those described in J. Berniers co-pending United States application Ser. No. 664,156 led on April 23, 1946. Such tubes are essentially formed by the association in parallel of a plurality of cells, each of which comprises an electron beam adapted to pass across a system of cavities of the shape of a prism with a rectangular or trapezoidal base, or of a sector of a cylinder bounded by two concentric surfaces. Said cavities are provided over the whole or a part of their height with a reentrant portion across which the beam is adapted to pass, and the successive cavities are arranged either in a straight line or in a circle, the system providing in the latter case a radially symmetrical tube.

One of the chief diihculties of construction encountered in this type of tube is the impossibility of tuning the cells in an eiiicient and simple manner by deforming their walls.

Certain devices proposed, such as inserting a piston into the inductive portion of the cavities, only give an extremely narrow tuning band.

The object of the invention is to enable simple tuning over a wide band to be obtained in tubes of this type.

The improvement according to the invention consists in a particular shape of the cavities used which will be more clearly understood from the ensuing description.

With said improvement are associated embodiments of the deforming means.

In vthe accompanying drawings:

Figs. l and 2 show in an explanatory manner a known shape of cavity which is used as a basis for the modifications according to the invention.

Figs. 3 to 6 show the cavities that form the rst improvement according to the invention.

Figs. 7 and 8 a multi-cellular klystron using a modification of the cavities of Fig. 3.

Fig. 9 shows the details of the deforming means used in Figs. '7 and 8.

Fig. 1 shows a vertical section, and Fig. 2 a sectional plan view taken along the line 2-2 of Fig. 1, of a cavity described in J. Berniers aforesaid application, said cavity essentially comprising a cylindrical sector bounded by two concentric surfaces I and 2 and by two radial surfaces 3 and 4.

Although the ensuing explanations refer to developments of this particular shape of the cavity, it is to be expressly understood that the invention does not rely on the particular shape of the cross-section shown: one of the cylindrical suitable s, France, assgnor to e Telegraphie Sans Fil, a

surfaces I and 2 could be replaced by a flat surface, or both the surfaces could be flat; in that case the cross-section would become a trapezium; by moving to innity the centre of the circumferences that bound the cross-section, the trapezium would be converted into a rectangle. The invention is applicable for the same reason to all these cases.

The cavity is provided with a tion 5 which does height of the body.

According to Figs. 3 and 4 corresponding to Figs. 1 and 2 and which show a rst stage of the improvement according to the invention, the portions 5 and 1 located outside the re-entrant portion 5 extend beyond same in the radial direction. In this manner a cavity is obtained, the walls of which may be made of such a shape, for example flat, as to permit readily of considerable deformations without changing the mean inductance of the resonator as compared to Figs. 1 and 2, since the decrease of inductance caused by the shape given to the walls is compensated by the increase of inductance due to the overlap of the proiile in the radial direction. Consequently, by acting in the direction of the arrows on the lateral surfaces 8 and s with deforming means known per se, a comparatively large variation of inductance is obtained and consequently a wide tuning band is provided.

The mean inductance and, consequently, the variations of inductance can be further increased at the expense of the capacitance of the resonator by giving to the re-entrant portion the shape of gradually tapering noses as shown in Figs. 3 and 4, since in this case the oppositely located surfaces ID and I I in the slit I2, which are the main factors that determine the capacitance of the resonator, are comparatively small.

According to Figs. 5 and 6, which corresponds to a second stage of the improvement and which show in its portion 6 a developed section of Fig. 5 along a circular axis 0-0, while Fig. 5 shows a sectional plan View along the line 5-5 of Fig. 6 in a similar manner to Figs. 2 and 4, the poroverlap the central portion not only 1n the radial direction but also in the an- In this manner, the inductance of the cavity is further increased, and furthermore the walls of the cavity bound spaces A which are connected to the exhausted space, and spaces B which cannot be exhausted. It is thus convenient to house in said spaces B deforming means which are adapted to act on the wall I3. It has been assumed that the cavity re-entrant pornot extend over the entire forms part of the inner circle of cavities of a radially symmetrical tube, and the Wall that bounds the vacuum round the cathode is shown at I6.

Figs. 'l and 8 show an example o the application of the, foregoing ideas to a radially symmetrical klystron of which Fig. 7 shows a modification of a section along the axis 'l of Fig. 6, and Fig. 8 shows an axial section of Fig. 7. rality of cathodes I1 are shown therein, each o which sends an electron stream across the cavities I8 and I9 constructed according to, the principles of Fig. 5, said stream being collected by the anode 20. The coupling between the cavities belonging to the same belt is obtained by merely eliminating the walls Hl and l5 of Fig. 6.

The Walls I3 and I3 are hinged on resilient flanges 2i and 2| and are subjected in the direction of the arrows to the thrust o the deformingineans 22 which are shown schematically, sussanded on uprignts 2-3 likewise shown schematically, said means being housed in the non-.exhausted spaces between the cavities and being actuated by means that can be readily" devised..

For example,y it is possible according to Fig. 9, to provide two blocks 24 and 25 which are guided by the stirrups 2li and are adapted to move along the screw-threaded rod 2,1. Said blocks are provided with inclined planes 2B which are adapted to bear against inclined planes 22 appertaining to the memmers 3l! nxed to the walls i3 and i3. to be deformed. By moving the blocks 2li and 25 towards one another a thrust is exerted on the walls i3 and is. In order to obtain the opposite movement when the rotation of the rod 2,1 is reversed, the members 3] are moved towards one another by means oi the thrust exerted by the inclined planes 31| secured tothe blockv 24 on tbe planes 32 of the members 3.8.. This system has the advantage of being able to be inserted with small bulk between two 1 neighborhood of the cavities and of being able to be actuated merely by a mechanism adapted to impart a rotary movement to the screw 21.

What I claim is:

l. A velocity modulation tube having circular symmetry and comprising a plurality of adjacent units, each unit comprising a cathode for emitting an electronic beam, a rst cavity resonator and a second cavity resonator traversed in succession by the electronic beam and an anode, the lateral surface of said resonators being donned by the translation in space ci a straight line perpendicular to. the plane. or symmetry of the tube, said resonators comprising further, in the immediate beam, re-entrant portions having bevelled edges, the first cavity resonators of the units. on the one hand and the second cavity resonators of all the units on the other hand being respectively connected to each other by at least two toroidal cavity resonators having an axis. of symmetry coinciding with the axis of symmetry of the tube.

2. A velocity modulation tube according to claim 1 wherein at least one Wall of each cavity resonator is deformable thereby to enable variaq tions of the space between the tapering edges, mechanical means being provided for displacing said edgesl along the electronic beam.

References Cited in the le 0i this. patent UNXTED STATES FATE'NTS 

